Backlight System

ABSTRACT

The present invention provides a backlight system, which includes a light source, a first primary assembling piece, a second primary assembling piece, a third primary assembling piece, a fourth primary assembling piece, a fifth primary assembling piece, a sixth primary assembling piece, and at least one secondary assembling piece. The first primary assembling piece, the second primary assembling piece, the third primary assembling piece, and the fourth primary assembling piece are joined to form a main frame structure of the back frame of the backlight system. The secondary assembling piece is arranged inside the main frame structure and joined to the main frame structure. The light source is arranged on the second primary assembling piece and the fourth primary assembling piece. The fifth primary assembling piece, the first primary assembling piece, the sixth primary assembling piece, and the third primary assembling piece are joined to form a central frame of the backlight system. The backlight system of the present invention has a simple structure, saves the material for back frame, and thus lowers down the cost of flat panel display device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of displaying techniques, and in particular to a backlight system of flat panel display device.

2. The Related Arts

The state-of-the-art liquid crystal display device comprises a front bezel, a panel, and a backlight module, of which the backlight module comprises a back frame, a reflector plate, a light guide, and a lighting assembly.

Currently, a variety of display panels of different sizes are available in the market to meet different needs of general consumers. For example, in the field of television set, the sizes of liquid crystal panels include 31.5, 42, 46, 48, and 55 inches. Different back frame molds are provided for liquid crystal planes of different sizes.

Referring to FIG. 1, FIG. 1 is a schematic view showing a conventional back frame of liquid crystal display device. As shown in FIG. 1, the conventional back frame 10 is a unitary back frame, and it is often that a unitary back frame 10 is made with metal stamping or plastic injection molding. The unitary back frame 10 consumes much material and has a high material cost. Further, a large-sized back frame 10 requires large-sized stamping equipment, and the size of mold corresponding to such a back frame 10 is large and the structure complicated, making the expenditure of the back frame mold high. As a consequence, the conventional back frame is of a high cost.

SUMMARY OF THE INVENTION

The technical issue to be addressed by the present invention is to provide a backlight system, which lowers material cost.

To address the above technical issue, the present invention adopts a technical solution that provides a backlight system, which comprises a back frame, a light source, a fifth primary assembling piece, and a sixth primary assembling piece. The back frame comprises a first primary assembling piece, a second primary assembling piece, a third primary assembling piece, a fourth primary assembling piece, and at least one secondary assembling piece. The first primary assembling piece, the second primary assembling piece, the third primary assembling piece, and the fourth primary assembling piece are joined to form a main frame structure of the back frame, and the secondary assembling piece is arranged inside the main frame structure and joined to the main frame structure. The light source is arranged on at least one of the second primary assembling piece and the fourth primary assembling piece. The fifth primary assembling piece, the first primary assembling piece, the sixth primary assembling piece, and the third primary assembling piece are joined to form a central frame of the backlight system.

According to a preferred embodiment of the present invention, the first primary assembling piece and the third primary assembling piece comprise a side wall and a first support section and a second support section that are spaced in a height direction of the side wall, the first support sections being joined to the second primary assembling piece and the fourth primary assembling piece; the second support sections are arranged to cooperate with the fifth primary assembling piece and the sixth primary assembling piece.

According to a preferred embodiment of the present invention, the first primary assembling piece, the third primary assembling piece, the fifth primary assembling piece, and the sixth primary assembling piece are plastic pieces; the second primary assembling piece and the fourth primary assembling piece are aluminum pieces or galvanized steel pieces.

According to a preferred embodiment of the present invention, the secondary assembling pieces comprise a first secondary assembling piece and a second secondary assembling piece, the first secondary assembling piece having two ends respectively joined to at least two primary assembling pieces of the first primary assembling piece, the second primary assembling piece, the third primary assembling piece, and the fourth primary assembling piece.

According to a preferred embodiment of the present invention, the first primary assembling piece has an end forming at least two joint sections, each of the joint sections having a structure mating an end of the second primary assembling piece, the first primary assembling piece using one of the joint sections to join the corresponding end of the second primary assembling piece.

According to a preferred embodiment of the present invention, the at least two joint sections are arranged to space from each other in a lengthwise direction of the first primary assembling piece.

According to a preferred embodiment of the present invention, the second primary assembling piece, the fourth primary assembling piece, the first secondary assembling piece, and the second secondary assembling piece are arranged parallel to each other.

According to a preferred embodiment of the present invention, the back frame comprises at least one bracing piece, which is releasably fixed to one or more of the first primary assembling piece, the second primary assembling piece, the third primary assembling piece, the fourth primary assembling piece, the first secondary assembling piece, and the second secondary assembling piece.

According to a preferred embodiment of the present invention, the bracing piece forms a bump.

According to a preferred embodiment of the present invention, the bracing piece is releasably fixed to one or more of the first primary assembling piece, the second primary assembling piece, the third primary assembling piece, the fourth primary assembling piece, the first secondary assembling piece, and the second secondary assembling piece.

The efficacy of the present invention is that to be distinguished from the state of the art, the present invention provides a backlight system that joins a first primary assembling piece, a second primary assembling piece, a third primary assembling piece, and a fourth primary assembling piece to form a main frame structure of the back frame and joins a fifth primary assembling piece, the first primary assembling piece, a sixth primary assembling piece, and the third primary assembling piece to form a central frame of the backlight system, so that the main frame structure of the back frame and the central frame share two of the assembling pieces that are not provided with light sources, namely the first primary assembling piece and the third primary assembling piece, thereby further saving the material for the back frame to lower down the manufacturing cost of flat panel display device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a conventional back frame of liquid crystal display device;

FIG. 2 is a schematic view showing a flat panel display device according to a first embodiment of the present invention;

FIG. 3 is a schematic view showing a back frame of a flat panel display device according to a second embodiment of the present invention;

FIG. 4 is a schematic view showing a back frame of a flat panel display device according to a third embodiment of the present invention;

FIG. 5 is a schematic view showing a back frame of a flat panel display device according to a fourth embodiment of the present invention;

FIG. 6 is a schematic view showing a joining structure of a flat panel display device according to a fifth embodiment of the present invention;

FIG. 7 is a schematic view showing a diagonally-arranged first secondary assembling piece mounted to a main frame structure of a flat panel display device according to a sixth embodiment of the present invention;

FIG. 8 is a schematic view showing a first secondary assembling piece and a second secondary assembling piece mounted to a main frame structure of a flat panel display device according to a seventh embodiment of the present invention;

FIG. 9 is a schematic view showing joint sections of a back frame of a flat panel display device according to an eighth embodiment of the present invention;

FIG. 10 is a cross-sectional view showing a first example of joint section of FIG. 9;

FIG. 11 is a schematic view showing a joining structure of a joint section of a back frame of a flat panel display device according to a ninth embodiment of the present invention;

FIG. 12 is a schematic view showing a joining structure of a joint section of a back frame of a flat panel display device according to a tenth embodiment of the present invention;

FIG. 13 is a schematic view showing a joining structure of a joint section of a back frame of a flat panel display device according to an eleventh embodiment of the present invention;

FIG. 14 is a schematic view showing a joint section of a back frame of a flat panel display device according to a twelfth embodiment of the present invention;

FIG. 15 is a schematic view showing a joint section of a back frame of a flat panel display device according to a thirteenth embodiment of the present invention;

FIG. 16 is a flow chart showing a method for manufacturing a back frame of a flat panel display device according to a fourteenth embodiment of the present invention;

FIG. 17 is a schematic view showing a flat panel display device with a touch screen according to a fifteenth embodiment of the present invention;

FIG. 18 is a schematic view showing a stereoscopic display device according to a sixteenth embodiment of the present invention;

FIG. 19 is a schematic view showing a plasma display device according to a seventeenth embodiment of the present invention;

FIG. 20 is a top plan view of a backlight module according to an eighteenth embodiment of the present invention;

FIG. 21 is a cross-sectional view taken along line A-A′ of FIG. 20; and

FIG. 22 is a cross-sectional view taken along line B-B′ of FIG. 20.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 2-3, FIG. 2 is a schematic view showing a flat panel display device according to a first embodiment of the present invention and FIG. 3 is a schematic view showing a back frame of a flat panel display device according to a second embodiment of the present invention. As shown in FIG. 2, the flat panel display device 20 according to the instant embodiment comprises: a backlight system 21 and a display panel 22. The backlight system 21 is arranged on a back side of the display panel 22 and supplies light to the display panel 22.

In the instant embodiment, the backlight system 21 comprises a light source 25, a light homogenization mechanism 24, and a back frame 23. The back frame 23 carries the light source 25 and the light homogenization mechanism 24. When the backlight system 21 is an edge lighting type, the light homogenization mechanism 24 is a light guide; and when the backlight system 21 is a direct type, the light homogenization mechanism 24 is a diffuser plate. The back frame 23 comprises at least a first primary assembling piece and a second primary assembling piece, and the two of at least first and second primary assembling pieces constitute a main frame structure 27 of the back frame 23.

Referring also to FIG. 3, the back frame 23 of the first embodiment comprises a first primary assembling piece 261 and a second primary assembling piece 262. The first primary assembling piece 261 has an end joined to an end of the second primary assembling piece 262, and the first primary assembling piece 261 has another end joined to another end of the second primary assembling piece 262 in order to form the main frame structure 27 of the back frame 23. The first primary assembling piece 261 and the second primary assembling piece 262 are both aluminum pieces or galvanized steel pieces. In the instant embodiment, the first primary assembling piece 261 and the second primary assembling piece 262 are L-shaped.

Referring also to FIG. 4, the back frame 23 of a second embodiment comprises a first primary assembling piece 281, a second primary assembling piece 282, and a third primary assembling piece 283. The three primary assembling pieces 281, 282, and 283 are assembled and joined to form a main frame structure 27 of the back frame 23. The three primary assembling pieces 281, 282, and 283 are all aluminum pieces or galvanized steel pieces. In the instant embodiment, the first primary assembling piece 281 is L-shaped, and the second and third primary assembling pieces 282, 283 are straight linear.

Further, the back frame 23 further comprises secondary assembling pieces arranged inside and joined to the main frame structure 27.

A detailed description will be given to the back frame 23 of the flat panel display device 20 according to the present invention, which comprises four primary assembling pieces and two secondary assembling pieces.

Referring to FIG. 5, FIG. 5 is a schematic view showing a back frame of flat panel display device according to a fourth embodiment of the present invention. As shown in FIG. 5, in the instant embodiment, a back frame 23 comprises: a first primary assembling piece 231, a second primary assembling piece 232, a third primary assembling piece 233, a fourth primary assembling piece 234, a first secondary assembling piece 235, a second secondary assembling piece 236, and bracing pieces 2371, 2372, 2373, 2374, 2375, 2376, and 2377. The first primary assembling piece 231, the second primary assembling piece 232, the third primary assembling piece 233, and the fourth primary assembling piece 234 are joined to each other in a leading end-to-tailing end manner to constitute a rectangular main frame structure 27 of the back frame 23. The first secondary assembling piece 235 and the second secondary assembling piece 236, serving as ancillary assembling pieces, are arranged in the main frame structure 27 and joined to the main frame structure 27.

Specifically, an end of the first primary assembling piece 231 is joined to an end of the second primary assembling piece 232, another end of the second primary assembling piece 232 is joined to an end of the third primary assembling piece 233, another end of the third primary assembling piece 233 is joined to an end of the fourth primary assembling piece 234, and another end of the fourth primary assembling piece 234 is joined to another end of the first primary assembling piece 231 in order to form the rectangular main frame structure 27. The first primary assembling piece 231, the second primary assembling piece 232, the third primary assembling piece 233, and the fourth primary assembling piece 234 are all aluminum pieces or galvanized steel pieces. In the instant embodiment, the first primary assembling piece 231, the second primary assembling piece 232, the third primary assembling piece 233, and the fourth primary assembling piece 234 are straight linear, yet in other embodiments, it is apparent to those skilled in the art to make all the first primary assembling piece 231, the second primary assembling piece 232, the third primary assembling piece 233, and the fourth primary assembling piece 234 L-shaped, or some being straight linear and the remaining being L-shaped. For example, in FIG. 3, the first primary assembling piece 261 and the second primary assembling piece 262 are both L-shaped; in FIG. 4, the first primary assembling piece 281 is L-shaped, while the second and third primary assembling pieces 282 and 283 are straight linear.

In the instant embodiment, the back frame 23 of the flat panel display device 20 is formed by joining connection. As shown in FIG. 6, an illustrative example is given for the connection of an end of the first primary assembling piece 231 to an end of the second primary assembling piece 232, wherein the end of the second primary assembling piece 232 is joined to the end of the first primary assembling piece 231 by means of for example screwing, fastening, or welding, to have the end of the second primary assembling piece 232 connected to the end of the first primary assembling piece 231.

In the instant embodiment, the first secondary assembling piece 235 and the second secondary assembling piece 236 are arranged in the main frame structure 27 of the back frame 23. An end of the first secondary assembling piece 235 is joined to the first primary assembling piece 231 and another end of the first secondary assembling piece 235 is joined to the third primary assembling piece 233; and an end of the second secondary assembling piece 236 is joined to the first primary assembling piece 231 and another end of the second secondary assembling piece 236 is joined to the third primary assembling piece 233. Further, the second primary assembling piece 232, the fourth primary assembling piece 234, the first secondary assembling piece 235, and the second secondary assembling piece 236 are arranged parallel to each other. In other embodiments, those skilled in the art may arrange at least one secondary assembling piece in the main frame structure 27. For example, only the first secondary assembling piece 235 is arranged in the main frame structure 27. Further, the two ends of the first secondary assembling piece 235 can be selectively joined to at least two of the primary assembling pieces of the first primary assembling piece 231, the second primary assembling piece 232, the third primary assembling piece 233, and the fourth primary assembling piece 234. For example, the first secondary assembling piece 235 is set diagonally in the main frame structure 27, as shown in FIG. 7. Similarly, the two ends of the second secondary assembling piece 236 can be selectively joined to at least two of the primary assembling pieces of the first primary assembling piece 231, the second primary assembling piece 232, the third primary assembling piece 233, and the fourth primary assembling piece 234. For example, the two ends of the first secondary assembling piece 235 are respectively joined to the first primary assembling piece 231 and the second primary assembling piece 232 that are adjacent to each other and the two ends of the second secondary assembling piece 236 are respectively joined the third primary assembling piece 233 and the fourth primary assembling piece 234 that are adjacent to each other, as shown in FIG. 8.

In the instant embodiment, the back frame 23 comprises seven bracing pieces 2371, 2372, 2373, 2374, 2375, 2376, and 2377. The bracing piece 2371 is fixed to the fourth primary assembling piece 234; the bracing pieces 2372, 2373 are both fixed to the first secondary assembling piece 235; the bracing piece 2374 is fixed to the second secondary assembling piece 236; the bracing piece 2375 is fixed to the second primary assembling piece 232; and the bracing pieces 2376, 2377 are each fixed, at two ends thereof, to the first secondary assembling piece 235 and the second secondary assembling piece 236. In practice, the bracing pieces can be fixed to one or more of the first primary assembling piece 231, the second primary assembling piece 232, the third primary assembling piece 233, the fourth primary assembling piece 234, the first secondary assembling piece 235, and the second secondary assembling piece 236. In other embodiments, those skilled in the art may mount bracing pieces of any other numbers to the back frame 23, such as one or more bracing pieces. Further, the bracing pieces can be releasably fixed to one or more of the first primary assembling piece 231, the second primary assembling piece 232, the third primary assembling piece 233, the fourth primary assembling piece 234, the first secondary assembling piece 235, and the second secondary assembling piece 236.

The bracing pieces 2371, 2372, 2373, 2374, 2375, 2376, and 2377 may be provided with bumps (not labeled) so that the back frame 23 may fix components, such as circuit boards, with such bumps.

Molds for making the back frame 23 will be described. In the instant embodiment, the first primary assembling piece 231 and the third primary assembling piece 233 are of the same size and shape so that they can be made by stamping with the same mold. The second primary assembling piece 232, the fourth primary assembling piece 234, the first secondary assembling piece 235, and the second secondary assembling piece 236 are of the same size and shape so that they can be made by stamping with the same mold, making it possible to share the mold. Thus, the back frame 23 of the present invention can be made by stamping with only two small-sized molds, and compared to the conventional back frame 10 that requires a large-sized mold, the molds for making the back frame 23 of the present invention are simple in structure and small in size and thus the cost of mold for the back frame 23 can be lowered. Further, compared to the whole back frame structure of the conventional back frame 10, the back frame 23 of the present invention can significantly save material used and thus reduce the manufacturing cost of the flat panel display device 20.

Referring to FIG. 9, FIG. 9 is a schematic view showing joint sections of a back frame of a flat panel display device according to an eighth embodiment of the present invention. As shown in FIG. 9, in the instant embodiment, an end of the first primary assembling piece is provided with two joint sections, and the joint sections have a structure mating an end of the second primary assembling piece so that the first primary assembling piece can be joined to a corresponding end of the second primary assembling piece.

Specifically, the first primary assembling piece 231 has an end forming joint sections 2311, 2312, and the joint sections 2311, 2312 are arranged in a spaced manner in a lengthwise direction of the first primary assembling piece 231. The joint sections 2311, 2312 are formed by forming recesses having a shape mating an end of the second primary assembling piece 232 in the first primary assembling piece 231 in order to receive the end of the second primary assembling piece 232 therein. As shown in FIG. 10, the joint sections 2311, 2312 are recesses that do not extend through opposite surfaces of the end of the first primary assembling piece 231 and the recesses are of a rectangular shape with the second primary assembling piece 232 being straight linear.

To assemble a large-sized back frame 23, the joint section 2311 that is close to the very end of the first primary assembling piece 231 is first taken and a second primary assembling piece 232 having a corresponding width is selected. Afterwards, an end of the second primary assembling piece 232 is positioned in the recess of the joint section 2311. And then, means, such as screwing, fastening, or welding, is applied to join and fix the end of the second primary assembling piece 232 to the joint section 2311. To assemble a small-sized back frame 23, the joint section 2312 that is distant from the very end of the first primary assembling piece 231 is first chosen and a second primary assembling piece 232 having a corresponding width is selected. Afterwards, an end of the second primary assembling piece 232 is positioned in the recess of the joint section 2312. And then, means, such as screwing, fastening, or welding, is applied to join and fix the end of the second primary assembling piece 232 to the joint section 2312. Specifically, for example the second primary assembling piece 232 forms a protrusion at a corresponding location on a surface thereof, and the protrusion of the second primary assembling piece 232 is embedded in the recess the first primary assembling piece 231 at a corresponding location in order to join the first primary assembling piece 231 and the second primary assembling piece 232, as shown in FIG. 11. Further, the second primary assembling piece 232 may form, on one end thereof, at least two protrusions that are spaced in the lengthwise direction of the second primary assembling piece 232, such as two, three, or four protrusions.

Furthermore, the recess of the first primary assembling piece 231 can be a recess of a multi-stepped configuration and the second primary assembling piece 232 forms, at a corresponding location, a protrusion having a multi-stepped configuration corresponding to the recess, as shown in FIG. 12. Further, as shown in FIG. 13, taking the joint section 2311 as an example, the recess of the first primary assembling piece 231 forms, in a bottom thereof, a first through hole 2313, and the second primary assembling piece 232 forms, at a location corresponding to the joint section 2311, a second through hole 2321. The back frame 23 further comprises a fastener 240. The fastener 240 extends through the first through hole 2313 and the second through hole 2321 to joint the first primary assembling piece 231 and the second primary assembling piece 232 to each other.

As shown in FIG. 14, in another embodiment of the back frame of flat panel display device according to the present invention, the recesses of the joint sections 2311, 2312 of the first primary assembling piece 231 are of a circular shape. Yet, in other embodiments, those skilled in the art may arrange the shape of the recesses to be other polygonal configurations, such as triangle.

As shown in FIG. 15, in another embodiment of the back frame of flat panel display device according to the present invention, the joint sections 2311, 2312 are recesses that do not extend through opposite surfaces of the first primary assembling piece 231, whereby an end of the second primary assembling piece 232 is movable within the joint sections 2311, 2312. For example, after the end of the second primary assembling piece 232 is set extending beyond and joined and fixed to the joint section 2312, the portion of extension is then trimmed off so that the length of the second primary assembling piece 232 that serves as a primary assembling piece of the back frame can be adjusted.

In a practical application, the other end of the first primary assembling piece 231 and both ends of the third primary assembling piece 233 are all provided with two joint sections having a structure identical to that of the joint sections 2311, 2312. The ends of the second primary assembling piece 232 and the ends of the fourth primary assembling piece 234 may be subjected to specific designs or no design at all according to the application. For example:

-   -   (1) In a first situation, as shown in FIG. 10, the two ends of         the second primary assembling piece 232 and the two ends of the         fourth primary assembling piece 234 are of no specific design.         In other words, the ends are of the same structure as the         remaining portions. Under this condition, in making a join with         a selected joint section 2311 (2312) at one end of the first         primary assembling piece 231 (the same applicable to the other         end), if an attempt is made to change the width of the back         frame 23, then the length of the corresponding second primary         assembling piece 232 and fourth primary assembling piece 234         must be selected accordingly. Namely, if the joint section 2311         that is close to the very end of the first primary assembling         piece 231 is selected for joining, then no trimming is applied         to the second primary assembling piece 232 and the fourth         primary assembling piece 234 or the portion that is trimmed off         is short; if the joint section 2312 that is distant from the         very end of the first primary assembling piece 231 is selected         for joining, then the second primary assembling piece 232 and         the fourth primary assembling piece 234 are trimmed and the         trimmed portion being long or short is according to the distance         that the joint section is from the very end of the first primary         assembling piece 231 being great or small; and     -   (2) In a second situation, it is similar to the first situation,         but as shown in FIG. 11, the second primary assembling piece 232         and the fourth primary assembling piece 234 use different         protrusions to respectively mate the first primary assembling         piece 231 and the third primary assembling piece 233 in order to         realize change of width of the back frame 23; similarly, if a         joint section 2312 other than the first joint section 2311 that         is close to the very end of the first primary assembling piece         231 is selected for joining, then before or after joining,         excessive portions of the second primary assembling piece 232         and the fourth primary assembling piece 234 may be trimmed off.

This also applicable to a main frame structure 27 of the back frame 23 that is formed by joining two L-shaped primary assembling pieces.

In summary, the present invention provides a back frame 23 having a first primary assembling piece that is provided with at least two joint sections. The number of the joint section can be selected according to the requirement of customers. In the instant embodiment, a description is given to an example comprising two joint sections 2311, 2312. Thus, to prepare the molds for making the back frame 23, only two sets of mold are needed, namely one mold for a first primary assembling piece and the other mold for a second primary assembling piece. The first primary assembling piece may be provided with a plurality of joint sections for joining operation in order to form various sizes for the back frame 23. To assemble the back frame 23, based on the desired size of the back frame 23, the corresponding one of the joint sections is selected. With the joint section, the second primary assembling piece is joined to the joint section of the first primary assembling piece and the other joint section of the first primary assembling piece that is located outward of the joining location of the second primary assembling piece is trimmed off to obtain a desired size of the back frame 23. Compared to the conventional technology that requires different back frame molds for making different sizes of back frame 10, the back frame of the flat panel display device 23 according to the present invention requires only a mold for the first primary assembling piece and a mold for the second primary assembling piece 28 so that mold sharing among various sizes of product can be realized and the molds used are of simple structures, allowing of reduction of expenditure of the molds for back frames.

The present invention also provides a mold for making a back frame of flat panel display device. The back frame mold is provided with a main pattern for forming a primary assembling piece of the back frame and the main pattern comprises a sub-pattern that forms at least two joint sections on an end of the primary assembling piece. The primary assembling piece comprises the previously discussed first primary assembling piece and second primary assembling piece, corresponding to the above mentioned main pattern; and the joint section comprises the previously discussed joint section of the first primary assembling piece, corresponding to the above mentioned sub-pattern. Repeated description is omitted herein.

As shown in FIG. 16, the present invention also provides a method for making a back frame of flat panel display device. The method comprises the following steps:

-   -   Step 501: manufacturing at least first and second primary         assembling pieces, in which the first primary assembling piece         has an end forming at least two joint sections, each of the         joint sections having a structure that mates a corresponding end         of the second primary assembling piece; and     -   Step 502: selecting one joint section of the at least two joint         sections according to a size of the back frame to join the         corresponding end of the second primary assembling piece.

In the instant embodiment, when other joint sections are present between the joining location of the second primary assembling piece and the end of the first primary assembling piece, before or after the step of selecting one joint section of the at least two joint sections according to a size of the back frame to join the corresponding end of the second primary assembling piece, the other joint sections of the first primary assembling piece that are located outward of the joining position of the second primary assembling piece are trimmed off. The first primary assembling piece comprises the previously discussed first primary assembling piece, and the second primary assembling piece comprises the previously discussed second primary assembling piece, and repeated description will be omitted herein.

As shown in FIG. 17, the flat panel display device 20 of the present invention further comprises a touch screen 29. The touch screen 29 is arranged on a light exit surface of the display panel 22 of the flat panel display device 20. The flat panel display device 20 comprises: the backlight system 21 and the above discussed display panel 22. The backlight system 21 is arranged at the back side of the display panel 22 and supplies light to the display panel 22.

The backlight system 21 comprises a light source 25, a light homogenization mechanism 24, and a back frame 23. The back frame 23 carries the light source 25 and the light homogenization mechanism 24. When the backlight system 21 is an edge lighting type, the light homogenization mechanism 24 is a light guide; and when the backlight system 21 is a direct type, the light homogenization mechanism 24 is a diffuser plate. The back frame 23 comprises at least a first primary assembling piece and a second primary assembling piece, and the at least one first and second primary assembling pieces constitute a main frame structure 27 of the back frame 23.

It is apparent that the backlight system 21 can be of a structure of any one of the previously discussed embodiments of the backlight system.

It is noted that the flat panel display device 20 of the present invention can be a liquid crystal display device or a liquid crystal television.

The present invention also provides a stereoscopic display device 30, as shown in FIG. 18. The stereoscopic display device 30 comprises a liquid crystal lens grating 31, a backlight system 32, and a display panel 33. The liquid crystal lens grating 31 is arranged on a light exit surface of the display panel 33. The backlight system 32 can be a backlight system of one of the above discussed embodiments, such as the backlight system 32 comprising the back frame 23. The back frame 23 comprises at least first primary assembling piece and the second primary assembling piece. The at least first and second primary assembling pieces form a main frame structure of the back frame. The backlight system 32 can be of a structure of any of the previously discussed embodiments of backlight system and repeated description will be omitted herein.

The present invention also provides a plasma display device 40, as shown in FIG. 19. The plasma display device 40 comprises a plasma display panel 41 and a back frame 42. The back frame 42 is arranged at a back side of the display panel 41. The back frame 42 can be the back frame of any of the previously discussed embodiments and repeated description will be omitted herein.

The present invention also provides an improved structure of backlight system. As shown in FIG. 20, in the instant embodiment, the backlight system 21 comprises a back frame 610, light sources 630, a fifth primary assembling piece 615, and a sixth primary assembling piece 616.

The back frame 610 comprises a plurality of primary assembling pieces and a secondary assembling piece 612. Specifically, the primary assembling pieces comprise a first primary assembling piece 611, a second primary assembling piece 612, a third primary assembling piece 613, and a fourth primary assembling piece 614. The first primary assembling piece 611, the second primary assembling piece 612, the third primary assembling piece 613, and the fourth primary assembling piece 614 are joined to form a main frame structure (not labeled) of the back frame 610.

The back frame 610 further comprises a secondary assembling piece 621, which is arranged inside the back frame 610 and joined to the main frame structure.

Further, the fifth primary assembling piece 615, the first primary assembling piece 611, the sixth primary assembling piece 616, and the third primary assembling piece 613 are joined to form a central frame (not labeled).

FIG. 21 is a cross-sectional view taken along line A-A′ of FIG. 20. As shown in FIG. 21, the first primary assembling piece 611 and the third primary assembling piece 613 comprise a side wall 6111 and a first support section 6112 and a second support section 6113 that are spaced from each other in a height direction of the side wall 6111.

FIG. 22 is a cross-sectional view taken along line B-B′ of FIG. 20. As shown in FIG. 22, the light sources 630 are mounted to the second primary assembling piece 612 and the fourth primary assembling piece 614. Certainly, in other embodiments, the light sources 630 can be mounted to only the second primary assembling piece 612 or the fourth primary assembling piece 614.

Collectively referring to FIGS. 21-22, the first support sections 6111 are provided for joining to the second primary assembling piece 612 and the fourth primary assembling piece 614 to form the main frame structure and also carrying a light guide plate 640. The second support sections 6113 are provided for forming, together with the fifth primary assembling piece 615 and the sixth primary assembling piece 616, the central frame of the backlight system 21 to carry a liquid crystal panel module 650.

In the instant embodiment, the first primary assembling piece 611, the third primary assembling piece 613, the fifth primary assembling piece 615, and the sixth primary assembling piece 616 are plastic pieces, while the second primary assembling piece 612 and the fourth primary assembling piece 614 are aluminum pieces or galvanized steel pieces.

As descried above, since the first primary assembling piece 611 and the third primary assembling piece 613 are common to both the back frame 610 and the central frame, a portion of the cost of the back frame is saved and thus, the cost of the back frame mold is indirectly saved. Further, since the central frame adopts a segmented structure, potential deformation occurring after molding can be prevented and thus the product yield can be improved.

The primary assembling pieces and the secondary assembling pieces of the instant embodiment can be those described in any one of the previously discussed embodiments. And, in the instant embodiment, no specific limitation is impose in respect of shape, structure, and joining manner of the primary assembling pieces and the secondary assembling pieces.

With the above discussed manners, the present invention provides a flat panel display device, a stereoscopic display device, and a plasma display device that have a mold for back frame that is of a simple structure and can reduce the expenditure for mold of back frame, and can also save the material used for back frame so as to lower down the cost of flat panel display device.

Embodiments of the present invention have been described, but are not intending to impose any undue constraint to the appended claims of the present invention. Any modification of equivalent structure or equivalent process made according to the disclosure and drawings of the present invention, or any application thereof, directly or indirectly, to other related fields of technique, is considered encompassed in the scope of protection defined by the clams of the present invention. 

What is claimed is:
 1. A backlight system, wherein the backlight system comprises: a back frame, the back frame comprising a first primary assembling piece, a second primary assembling piece, a third primary assembling piece, and a fourth primary assembling piece and at least one secondary assembling piece; the first primary assembling piece, the second primary assembling piece, the third primary assembling piece, and the fourth primary assembling piece being joined to form a main frame structure of the back frame, the secondary assembling piece being arranged inside the main frame structure and joined to the main frame structure; a light source arranged on at least one of the second primary assembling piece and the fourth primary assembling piece; and a fifth primary assembling piece and a sixth primary assembling piece, in which the fifth primary assembling piece, the first primary assembling piece, the sixth primary assembling piece, and the third primary assembling piece are joined to form a central frame of the backlight system.
 2. The backlight system as claimed in claim 1, wherein: the first primary assembling piece and the third primary assembling piece comprise a side wall and a first support section and a second support section that are spaced in a height direction of the side wall, the first support sections being joined to the second primary assembling piece and the fourth primary assembling piece; the second support sections are arranged to cooperate with the fifth primary assembling piece and the sixth primary assembling piece.
 3. The backlight system as claimed in claim 2, wherein: the first primary assembling piece, the third primary assembling piece, the fifth primary assembling piece, and the sixth primary assembling piece are plastic pieces; the second primary assembling piece and the fourth primary assembling piece are aluminum pieces or galvanized steel pieces.
 4. The backlight system as claimed in claim 3, wherein: the secondary assembling pieces comprise a first secondary assembling piece and a second secondary assembling piece, the first secondary assembling piece having two ends respectively joined to at least two primary assembling pieces of the first primary assembling piece, the second primary assembling piece, the third primary assembling piece, and the fourth primary assembling piece.
 5. The backlight system as claimed in claim 1, wherein: the first primary assembling piece has an end forming at least two joint sections, each of the joint sections having a structure mating an end of the second primary assembling piece, the first primary assembling piece using one of the joint sections to join the corresponding end of the second primary assembling piece.
 6. The backlight system as claimed in claim 5, wherein: the at least two joint sections are arranged to space from each other in a lengthwise direction of the first primary assembling piece.
 7. The backlight system as claimed in claim 6, wherein: the second primary assembling piece, the fourth primary assembling piece, the first secondary assembling piece, and the second secondary assembling piece are arranged parallel to each other.
 8. The backlight system as claimed in claim 6, wherein: the back frame comprises at least one bracing piece, which is releasably fixed to one or more of the first primary assembling piece, the second primary assembling piece, the third primary assembling piece, the fourth primary assembling piece, the first secondary assembling piece, and the second secondary assembling piece.
 9. The backlight system as claimed in claim 8, wherein: the bracing piece forms a bump.
 10. The backlight system as claimed in claim 8, wherein: the bracing piece is releasably fixed to one or more of the first primary assembling piece, the second primary assembling piece, the third primary assembling piece, the fourth primary assembling piece, the first secondary assembling piece, and the second secondary assembling piece. 